Method of making electrical components



Sept. 26, 1961 J. D. HEIBEL ET AL METHOD OF MAKING ELECTRICAL COMPONENTSFiled Dec. 8, 1954 F194 FIQZ ma FIG. 5 7 9 INVENTORS Jerome D. HeibelUnited States. Paten 0.

p 3,001,267 METHOD OF MAKING ELECTRICAL COMPONENTS I and Nell'o Coda,Erie, Pa., assignors to Erie Resistor Corporation, Erie, Pa., acorporation of Pennsylvania Filed Dec. 8, 1954, Ser. No. 473,832

2 Claims. (Cl. 29 -1555) Thisinvention is intended to provide circuitcomponents such as resistors and capacitors with a wrapped plasticinsulating case and with lead wires at each end having solderedconnections to the terminal surfaces of thecomponents.

In the accompanying drawing, FIG. 1 is a section through a capacitorwith a wrapped plastic insulating case; FIG. 2 shows a resistor whichcould be substituted of the tube and terminates in a terminal surface 4.The

outer electrode coating terminates in a terminal surface at the oppositeend of the tube. The electrodes 2 and 3 of the terminal surfaces 4 and15canconveniently be applied by one of the silver paints used in thedecoration of ceramics and when fired on the tubular ceramic body 1produces a metallized coating which is securely attached to the ceramic.The construction so far described is cornmon to ceramic capacitors andmay vary substantially in appearance from'the particular capacitorillustrated.

In FIGS. 2, 3, and'4 is shown a resistor having acylindrical body 6which may, for example, be carbon particles bonded together with asuitable plastic. At

one end, the resistor has a terminal surface 4a which is formed by ametallic band 7 wrapped around and molded in place on the body 6 ofresistance material. At the other end of the resistor is a terminalsurface 5a which comprises two semi-cylindrical metal parts 8 likewisemolded to the body of resistance material. Other expedicnts forproviding terminal surfaces on the resistance body are known; forexample, the metal spraying technique.

Either the capacitor of FIG. 1 or the resistor of FIGS. 2, 3, and 4which may be considered as typical electric circuit components, requireleads for making the circuit connections and a protective insulatingcase. In FIG. 1 is shown a construction for providing both theinsulating case and the leads and in FIG. 5 is shown one form of plastictape which can be utilized in the FIG. 1 construction. The constructionof FIG. 1 is obviously usable with either of the electric circuitcomponents.

Around each of the terminal surfaces 4 and 5 is wrapped a thin metalliccylinder 9which may, for example, consist of a thin tinned copperribbon. The cylinder 9 may be wrapped separately, or as shown in FIG. 5,the cylinder 9 may comprise two metal portions 9a on opposite edges of astrip of plastic tape 10a. The portions 9a maybe metallized coatings onthe tape. The

:the first turn is used.

ice

length of the portions 9a is not important since only It may be moreeconomical to have the portions 9a in the form. of continuous stripesextending the full length of the tape. As shown in FIG. 1, a pluralityof layers of plastic tape 10 are wrapped around the body of thecondenser and over the cylindrical metal parts 9. With the FIG. 5 tape,the first turn would form cylindrical parts 9a. The tape projects aslight distance beyond the ends of each ofthe metal members 9 asindicated at 11 thereby increasing the insulation leakage resistancepath. The tape 10 may be resin impregnated paper, resin impregnatedfabric, or straight plastic resin. If the tape has the property ofbonding to itself, there is no need for using an additional adhesive. Ifthe tape does not have the property of bonding to itself, an additionaladhesive may be applied; The plastic may be thermosetting, or theplastic may be completely cured and the adherence between the diiferentlayers may be obtained by the adhesive. Suitable tapes are availableunder the trade name Mylar Tape, which is a polyester resin tape, backedwith a thermosetting adhesive; Teflon Tape in the cured staate with athermosetting adhesive; Teflon Tape with the resin in the B, orpartially cured stage, which requires no additional adhesive, but isself-adhering; Kel-F 'Tape, which is adhesive-backed; Plaskon 412 Puttyextruded in tapeform; glass cloth tape impregnated with a thermosettingresin such as an epoxy, silicone, or polyester resin of the solventlessvarnish type; or a polyester film similar to that used as an adhesivefilm for adhering foil to plastic in the printed circuit art. All thesetapes provide the desired insulating case and, in addition, provide thedesired firm contact between the metallic cylinders 9 and the terminalsurfaces 4 and 5. The metallic cylinders 9 are quite thin since they areused only for making the connections to the terminal surfaces. Afterwrapping, the tape is cured or is set in place by heat. In some cases,the plastic itself is cured, while in other cases, only the adhesivebetween the plastic tape layers is cured. At the end of the curingoperation, the wrapped tape will be consolidated and, in many cases,there will in addition he a shrinkage of the tape which brings it intointimate contact with the outside of the condenser. Mylar and Kel-Ftapes have the property of shrinking upon ouring so as to produce acompression grip on the circuit component which is desirable.

At each end of the component are lead wires 12, each having a flat,round head 13 telescoped within'the cylindrical metal parts 9. The shapeof the head is not critical. Although the head 13 is formed byupsetting, it could be formed by winding the end of the lead in aspiral. A solder connection is made, as indicated at 14, between the rimof the head 13 and the cylindrical part 9 and there is also a solderconnection, as indicated at 15, between the cylindrical part 9 and theadjacent terminal surface 4 or 5, as the case may be. The solder for theconnections -14 and 15 may come from a soldercoating applied to thecylindrical metal part 9 and the head 13, or it may come fromdip-soldering or other available methods. When the soldering connectionis completed, the solder seals the heads 13 into the ends of the plasticcase and provides the lead wires 12 desirable for connecting thecomponent into electric circuits.

It is obvious that the resistor of FIGS. 2, 3, and 4 in FIG. 1. In fact,any other electric circuit element can be substituted.

When the FIG. 5 tape is used, the initial layer of the projectingaXiallyfrom opposite ends from an element having a rigid cylindricalbody with an external terminal surface at each end of the body, which.comprises'wrapping a metal band over theterrninal surface at one end 7of the'body, wrapping another metal handover the terminal surface at theopposite end of the body, each of the bands havinga part overhanging theend on which "it is Wrapped and providing an open ended pocket,

Wrapping a plurality of layers of adhesive tape of insulating materialaround the body and b ands, position ing apair of leads to projectaxially from oppositefe'nds of the element with one end of each lead'inone of the pockets, and soldering said one end of each lead to thepocket in which it is positioned.

8,001,267 l s. p e

2. The method 0501mm 1 in w ch the metal bands are attached to the innersurface of that part of the tape forming the initial layer when wrappedaround the body.

References Cited in the file of this patent UNITED STATES PATENTS1,990,819 Danziger Feb. 12, 2,057,790 Potter Oct. 20, 1936, 2,361,405Kopple Oct. 31, 1 944 1 2,452,540 Barnard, Nov. 2, 1948 2,522,713 GraySept. 19,1950 1 2,557,571 Siegel June 19, 1951 2,640,132 Thom May 26,1953 2,675,421 Dexter f..... Apr. 13, 1954 2,677,746 Duch et a1. May 4,1954 2,751,665 De Roovere June 26, 1956 2,769,944 Stein Nov. 6, 19562,792,620 Kohring May 21, 1957 2,803,729 Kohring "Aug. 20, 1957 FOREIGNPATENTS 657,787 Germany Mar. 12, 1938 120,052 Australia June 5, 19451952 842,815 Germany July 3,

